Field of the Invention
The present invention relates to a transmission and more particularly relates to a transmission, particularly for a motorcycle, which has a torque converter which operates to couple the engine to the output shaft at low speeds and which at higher speeds establishes a direct mechanical connection between the engine and the output shaft.
Some motorcycles utilize automotive engines such as Chevrolet V-6 or V-8 engines. Currently there are approximately ten manufacturers of automotive engine power motorcycles on the market. Representative of these is the Kannon V-cycle which is manufactured using both V-6 and V-8 engines. Motorcycles with engines of this type share a common problem. In order to travel at speeds of less than thirteen miles per hour, the motorcycle rider must slip a hand-held clutch. Since there is no neutral lock-out, the motorcycle remains in gear at all times. This results in serious disadvantages as the rider does not have full control of the motorcycle when the clutch is in the slipped position. Further problems can arise if the rider accidently releases the clutch suddenly engaging the transmission causing the motorcycle to lurch causing a loss of control. Another problem attendant to conventional transmissions used with large block motorcycles is that slipping the clutch results in unnecessary and premature wear of the clutch mechanism.
In view of the foregoing, there is a demonstrated need for an improved mechanism for shifting motorcycles of the type utilizing automotive engines which is safer, effective and convenient to use.
There are a number of motorcycle transmissions commercially available and the patent literature discloses a number of drive mechanisms which are represented by the following:
U.S. Pat. No. 2,943,515 discloses a power transmitting apparatus, particularly one employing a hydro-kinetic type of torque transmitting unit in combination with a chain speed gear box transmission unit with a plurality of selectively operable clutch means. PA1 U.S. Pat. No. 4,079,820 discloses a rotary power transmission having a hydrodynamic speed or torque converter or other fluid coupling in combination with a magnetically actuated friction clutch. The friction clutch is accommodated inside the housing of the fluid coupling and the magnet which actuates the friction clutch located outside the housing and the magnetic field generated is effective through the housing. PA1 U.S. Pat. No. 4,673,071 discloses a power delivery system which includes an input shaft and an output shaft disposed concentrically with the input shaft, a fluid coupling and a power cut-off device interposed between the input and output shafts. The case containing the fluid coupling is located on a radial inner side of the fluid coupling and an oil pump for supply of oil into the fluid coupling case is positioned within the case adjacent the radially inward periphery of the power cut-off device. PA1 U.S. Pat. No. 4,733,761 discloses a power delivery system including an input shaft for transmitting driving power of an engine, an output shaft mounted concentrically with the input shaft, a pump mounted concentrically between the input and output shaft and connected to the input shaft, a fluid coupling having a turbine connected to the output shaft, the case containing the fluid coupling and a power cut-off device. The power cut-off device is provided with a frictional coupling element and a servo mechanism. PA1 U.S. Pat. No. 4,667,762 discloses a drive mechanism for a motorcycle having a rear wheel which is supported by a trailing arm and is driven by a drive that includes an intermediate shaft that is rotatably journaled on the trailing arm. One end of the intermediate shaft is driven from the engine output shaft by a drive shaft and the other end of the intermediate shaft drives the rear wheel through a chain. The chain is positioned a substantially greater distance outwardly of the longitudinal center line of the motorcycle than is the drive shaft so as to afford good driver position and a relatively narrow width. PA1 U.S. Pat. No. 5,263,549 also discloses a motorcycle shaft drive mechanism and a drive gear located on a drive shaft for rotation and axle gear located on the rear axle for driving the rear axle. A pinion shaft is provided having a front pinion gear matching the drive gear and a rear pinion gear matching the rear axle so that when the drive shaft is driven, the force supplied by the drive gear to the front pinion gear creates a moment on the pinion shaft about the drive shaft which is opposite to and balances the moment on the pinion shaft about the rear axle.